This invention relates to an apparatus for supporting product during cutting, and more particularly, to supporting product for cutting by a saw which transversely severs multi-ply material such as logs of bathroom tissue or kitchen toweling.
In the production of rolls of bathroom tissue or kitchen towels, a jumbo sized parent roll of web material is unwound, transversely perforated, and rewound into a log which has the diameter of the final product. The log is cut into individual rolls of bathroom tissue or kitchen towels by a log saw.
Rewinders are described, for example, in U.S. Pat. No. 6,056,229 and U.S. Pat. No. Re. 28,353 and EPO 0 694 020B1.
Log saws are described, for example, in U.S. Pat. No. 6,123,002, U.S. Pat. No. Re. 30,598, and U.S. Pat. No. 5,315,907.
In all present log saw assemblies, the log is advanced axially toward the path of the blade, which passes transversely through the log. The log is supported upstream of the blade, and the cut rolls plus the roll which is being cut are supported downstream of the blade.
The problems with current log saws vary depending upon the log saw. In some designs, as is shown in U.S. Pat. No. 5,315,907, the support is rigid, as is needed, but conforms to only one diameter of log for optimum cutting quality. This is also true of co-owned U.S. Pat. No. Re. 30,598. Change parts are required for handling large differences in product diameter.
In the assemblies shown in U.S. Pat. Nos. 5,357,833 and 5,647,259, the strips and straps that support the product are made flexible to allow adjustment for product diameter. These strips and straps have the elastic tendency to expand, in other words, straighten. Therefore, the strips and straps will seek a larger bending radius until forced to a smaller one, thereby not forming a true circle for the product.
The mechanism used for product diameter adjustment must be simple and make it easy for the person making the adjustment. In the assembly as shown in U.S. Pat. No. 5,357,833, two independent adjustments are required for variations in product diameter, one for the strap and the other for the oscillating cradles. Fine-tuning between them is required due to the elastic tendency of the strips and straps to expand.
In U.S. Pat. No. 5,647,259, which is an improvement over U.S. Pat. No. 5,357,833, a more complicated assembly was devised to achieve a coarse product diameter adjustment of the straps and cradles simultaneously with one drive. Based on the elastic tendency of the strips ard straps to expand, fine tuning, which is actually a second adjustment, is required to accommodate products of different diameters.
The converting industry is in need of an assembly that is not only rigid, but that provides sufficient contact with, or guiding for, the product throughout the full diameter range of the product. The apparatus used to achieve this should involve a single mode of adjustment. To solve this problem, a novel type of support assembly was invented, utilizing pivotable lower links, on which the product rides, guided by the components of the movable upper supporting assembly during adjustment for diameter variations. The invention provides an apparatus for an adjustable supporting assembly for the cutting of logs throughout an entire diameter range by way of a single adjustment mechanism, without the changing of any components or secondary fine tuning.
The invention includes two product support assemblies, one upstream and one downstream of the blade path. The support assemblies can be set up for single or multiple lanes of product. Each support assembly includes non-adjustable stationary guides above the product. The guides are formed so as to support product through a portion of the diameter range. The shape of these guides also controls the position of the links of a pivotable lower supporting assembly during adjustment for various product diameters. As the upper support assembly is raised, the links move to provide a larger opening through which the product moves. As the upper assembly is lowered, a smaller opening is provided. Raising and lowering of the upper support assembly can be done manually or by power.